The present invention relates to avionics. Modern commercial/private aircraft, as well as older aircraft, generally include a myriad of instrumentation panels associated with electronic devices having controls, displays, and software applications, which are used to present information to pilots and/or copilots during flight. The electronic devices, controls, displays and applications are interfaced together to form avionics equipment within the aircraft. Pilots (where “pilot” includes copilots and any other controller of the aircraft) access one or more interface devices of the avionics equipment prior to and during the flight. Some of this information presented monitors the status of equipment on the aircraft, while other switches and knobs are used to control functions of the aircraft such as throttles (engine speed), switches (lights, radios, etc), levers (landing gear and flaps), and controls for navigation, for example.
Recently, aircraft are moving away from mechanical and analog avionics to digital avionics. This greater demand on the electrical system has given rise to the need for intelligent power distribution systems. Some power distribution systems may be suitable for use in aircraft, for example those described in U.S. Pat. No. 5,864,221 (Dedicated avionics standby power supply); U.S. Pat. No. 5,723,915 (Solid state power controller); U.S. Pat. No. 5,497,072 (Solid state power controller with power switch protection apparatus); and U.S. Pat. No. 4,409,635 (Electrical power system with fault tolerant control unit); each of which is incorporated herein by reference. Some proposed power distribution systems use microprocessors and solid-state switches (Field Effect Transistors or similar) to switch devices on and off. However, in the case of flight critical devices that require constant power, a failure of the microprocessor or solid-state switch could adversely affect the safety of flight. Currently there are no intelligent backups for this type of failure.